Experiment on methane displacement in coalbed by supercritical carbon dioxide

Using self-made experimental system, experiments were performed on coal samples to study supercritical CO₂ seepage, adsorption and CH₄ displacement by supercritical CO₂. Experimental results show that permeability and adsorption of supercritical CO₂ in coal increase with CO₂ pressures. Pressures and temperatures of CO₂ influence the values of displaced CH₄. Values of displaced CH₄ increase by average 0.076 cm³/g and sweep efficiency rises by 17%-23% with the CO₂ pressure increasing from 8 MPa to 12 MPa, while displacement volume decreases linearly. With the temperature rising by 10℃, sweep efficiency increases by 8% while displacement volume declines by 0.5 on average.